1. Field of the Invention
The present invention relates to weatherstrips, and more particularly to an improved weatherstrip mountable within a slot in one member for sealingly engaging another relatively movable member.
2. Description of the Prior Art
British Patent Specification No. 1,507,071 discloses a weatherstrip mountable within a slot and having an elongated body of resilient foamed synthetic resin material. The weatherstrip has an elongate anchorage member more rigid than the body and formed of synthetic resin material. The body has a narrow neck portion joined to the anchorage member. A skin of synthetic resin material encloses and is secured to the body and anchorage member.
A weatherstrip similar to the weatherstrip disclosed in British Specification No. 1,507,071 is known in which the anchorage member of synthetic resin material is replaced by an anchorage member of paper having a low coefficient of thermal expansion.
U.S. Pat. No. 3,761,347 discloses a pressure sensitive weatherstrip formed of a length of resilient material having a pair of legs extending outwardly at about a right angle to each other. The free ends of the legs curve back on themselves and extend inwardly at acute angles to the legs. The weatherstrip has a third anchoring leg of hookshaped cross section for insertion into a slot.
The prior art weatherstrips are made in indefinite lengths and then cut to the desired lengths for particular installations. The weatherstrip can be used to seal the space between any two relativey movable members, such as windows and doors relative to window and door frames, for example. A problem occurs where the seal surfaces abruptly deviate from a straight path, for example at the corners of a window or door. In such cases, an attempt to bend the weatherstrip at right angles causes deep wrinkling of the weatherstrip at the corner resulting in leakage to occur there. To overcome this problem, the weatherstrip is cut into pieces instead of using a continuous strip, and the abutting or overlapping ends of two strips at a corner are sealed together. This procedure is time consuming and not completly effective in eliminating air or moisture leakage at the corner.
A second problem relates to the use of weatherstrips in applications where the ambient temperature changes greatly such as from season to season. Where such weatherstrips are made from plastic material such as those shown in U.S. Pat. No. 3,761,347, the length of a long section of weatherstrip may change substantially as the temperature changes so that, for example, in the winter, the weatherstrip shrinks leaving gaps at the ends and does not completely seal a door or window.